The present invention is an improved magnetic head suspension assembly (HSA) for use with dynamic magnetic storage devices or rigid disk drives. More exactly, it is a head suspension assembly that has a one-piece structure constructed with a load beam and a flexure region. Specifically, this invention describes improvements in the construction of the flexure region to improve dynamic performance of the HSA, decrease pitch and roll stiffnesses, increase lateral and in plane stiffnesses, improve manufacturability, and improve head bond location.
Conventionally available magnetic head suspension assemblies for rigid disk drives allow magnetic read/write heads to pitch about a first or transverse axis and roll about a second or longitudinal axis, orthogonal to the first axis, when imperfections in the disk drive assembly tend to place the heads in improper positions relative to the associated disk surface. The present invention allows significant reductions in the pitch and roll stiffness of the head suspension assembly, thus allowing the heads to easily maintain proper attitude to the disk. At the same time, the present invention increases stiffness in the direction of rotation of the disk to maintain proper head position with respect to the suspension assembly. Further, the invention resists permanent distortion to the HSA which can be caused by forces in all directions.
Conventional head suspension assemblies consist of a support baseplate, load beam, and flexure, which are usually separately etched, stamped and then welded together. According to the present invention, the flexure is constructed as an integral part of the load beam, which reduces manufacturing steps and improves the ability to manufacture the HSA with the proper head position and attitude.
Conventional head suspension attachments or base plates are welded to the load beam and attached to an actuator arm and are generally configured for swage or screw attachment means. As described in commonly assigned U.S. Pat. No. 5,198,945, issued Mar. 30, 1993, the attachment means is an integral part of the load beam. This method of attachment avoids welding, thus reducing process steps, easing disk drive assembly, and improving the ability to position the head properly with respect to the actuator arm. The load beam attaches to the actuator arm by an attachment means employing an interference fit, such as a clip.
As also described in U.S. Pat. No. 5,198,945, the load beam can be attached to the actuator arm by a shrink fit interference means encircling the arm and load beam(s). Such a shrink fit can be performed by heating the shrink fit interference means to expand and then contract around the actuator arm and load beam(s), or by heating the shrink fit interference means to simply contract around the actuator arm and load beam(s). This method of attachment reduces the number of components and process steps, and allows the HSA to be attached to and removed from the actuator arm easily.
Conventional means for positioning and aligning the read/write head to the suspension assembly, when attaching the head suspension assembly to the actuator arm, is to place an alignment pin through a hole in the load beam, another alignment pin through a hole(s) in the baseplate, and mount the baseplate and the actuator arm with screws or with the baseplate boss. As also described in U.S. Pat. No. 5,198,945, an alignment pin is positioned through a hole in the load beam and another alignment pin is positioned through a slot at the base end to improve the accuracy and ease of positioning the head with respect to the suspension assembly and to facilitate the alignment of the head suspension assembly with respect to the actuator arm. As can be readily understood, this arrangement may equally well be reversed, with a hole positioned in the base end and a slot positioned in the load beam. The pin/hole registration will keep the parts aligned in the x and y directions, while the pin/slot registration keeps the parts from rotating about the z axis. Further, a single one-piece suspension structure constructed with both a load beam region and a flexure region eliminates the tolerance build up from welding three separate components together and allows the head location to depend solely on the precision manufacture of the holes and slots.
Conventionally available magnetic head suspension assemblies have load beams with rails extending either away from the rigid disk or toward the rigid disk, as shown in commonly assigned co-pending application Ser. No. 08/050,517, filed Apr. 20, 1993, which in turn is a continuation of Ser. No. 07/583,048, filed Sep.14, 1990, now abandoned.
In the prior art, the rail oriented to project from the surface of the load beam, away from the associated disk surface, offered increased clearance between the disk and the load beam for lifting the load beam, while the rail oriented toward the disk surface offered increased clearance between two back to back head suspension assemblies and allowed for closer disk spacing. The present construction offers increased clearance on both sides of the head suspension assembly for lifting the load beam and for allowing closer disk spacing. U.S. Pat. No. 5,198,945 uses a rail form line that is not parallel to the disk surface over its entire length but is closer to the disk at the slider end and withdrawn from the disk at the base end, such that the lift clearance can be maximized near the base plate and the disk spacing clearance can be maximized near the slider.